How to Write Parser in PHP

Transcript

1. Jan Tvrdík
4. process of splitting text into words The square is blue . The square is blue.
5. process of organizing sequence of words into structure The square is blue .
6. The square is blue . D N V A NP VP S
7. process of given meaning to the word structure
8. normally done by simple state machine fastest state machine in PHP = PCRE
11. can be optimized to a single preg_* call by using a smart trick David Grudl has taught me
13. ready to use lexer = nette/tokenizer
14. always start by writing a grammar EBNF simple not standardized ABNF slightly less friendly than EBNF standardized by IETF PEG the coolest not standardized
15. multiple approaches possible easiest to start with is recursive descent parser because it matches the grammar
16. JsonValue = JsonBool / JsonNull / JsonNumber / JsonString / JsonArray / JsonObject JsonBool = TokenTrue / TokenFalse JsonNull = TokenNull
17. JsonNumber = TokenNumber JsonString = TokenString JsonArray = TokenSquareBracketOpen JsonArrayItems? TokenSquareBracketClose JsonArrayItems = JsonValue (TokenComma JsonValue)* ...
19. Twitter + GitHub @JanTvrdik